diff --git a/ChangeLog b/ChangeLog
index e791f69d..605ea522 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -7,6 +7,8 @@
 	* src/text.c (do_indent): Also here discard the entire undo stack, to
 	prevent nano from making mistakes when trying to undo edits after an
 	indentation change.  This works around Savannah bug #46591.
+	* doc/man/nano.1, doc/texinfo/nano.texi: Add a note about undo not
+	working after a justification or reindentation.
 
 2015-12-02  Benno Schulenberg  <bensberg@justemail.net>
 	* doc/syntax/python.nanorc: Don't colour triple quotes by themselves.
diff --git a/doc/man/nano.1 b/doc/man/nano.1
index ce3b1971..320942b5 100644
--- a/doc/man/nano.1
+++ b/doc/man/nano.1
@@ -275,7 +275,13 @@ it unique.  In multibuffer mode, \fBnano\fP will write all the open
 buffers to their respective emergency files.
 
 .SH BUGS
-Please report any bugs that you encounter via
+Justifications (\fB^J\fR) and reindentations (\fBM-{\fR and \fBM-}\fR)
+are not yet covered by the general undo system.  So after a justification
+that is not immediately undone, or after any reindentation, earlier edits
+cannot be undone any more.  The workaround is, of course, to exit without
+saving.
+.sp
+Please report any other bugs that you encounter via
 https://savannah.gnu.org/bugs/?group=nano.
 
 .SH HOMEPAGE
diff --git a/doc/texinfo/nano.texi b/doc/texinfo/nano.texi
index e0e59422..1d232337 100644
--- a/doc/texinfo/nano.texi
+++ b/doc/texinfo/nano.texi
@@ -386,6 +386,7 @@ Ignored, for compatibility with Pico.
 * The Statusbar::
 * Shortcut Lists::
 * Using the Mouse::
+* Limitation::
 @end menu
 
 @node Entering Text
@@ -490,6 +491,15 @@ Shift key during those actions.
 The mouse will work in the X Window System, and on the console when gpm
 is running.
 
+@node Limitation
+@section Limitation
+
+Justifications (@code{^J}) and reindentations (@code{M-@{} and @code{M-@}})
+are not yet covered by the general undo system.  So after a justification
+that is not immediately undone, or after any reindentation, earlier edits
+cannot be undone any more.  The workaround is, of course, to exit without
+saving.
+
 
 @node Built-in Help
 @chapter Built-in Help